Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6349627 | Palaeogeography, Palaeoclimatology, Palaeoecology | 2015 | 13 Pages |
Abstract
Elevation estimates based on the dead foraminiferal faunas in replicate salt-marsh cores 10Â m apart indicate a subsidence event of ~Â 0.15-0.2Â m at 45Â cm downcore. This was probably a result of shaking-induced lateral spread of the marsh into the river channel during a late 19th century earthquake-most probably the 1869 Christchurch Earthquake. A second possible co-seismic subsidence event is indicated at 80Â cm downcore but the MAT elevational estimates are less reliable because of the low density foraminiferal faunas. A sudden relative fall in sea-level (or uplift of land) of 0.2-0.25Â m is indicated by MAT elevation estimates at 60Â cm downcore. As there is no known supporting evidence for a tectonic uplift event, we infer the most likely explanation is that this event spans an erosional time break (>Â 500Â yrs). Although we did not recognise its significance at the time, the foraminiferal record in our 2009 salt marsh core indicated that Christchurch had previously experienced significant co-seismic shaking on at least one, and maybe more, occasions within the last 1000Â yrs.
Keywords
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Earth-Surface Processes
Authors
Bruce W. Hayward, Ashwaq T. Sabaa, Brigida Figueira, Catherine M. Reid, Ritsuo Nomura,